The MEF [In Silverlight Application] Part-III

MEF –Managed Extensibility Framework also Part of  Silverlight. If you happened to land directly  In this blog post i would suggest to read the part I and Part II of this series.

Here is the Links for Part 1 & Part II

http://mstecharchitect.blogspot.com/2010/02/mef-managed-extensibility-framework.html –PART I

http://mstecharchitect.blogspot.com/2010/02/mef-managed-extensibility-framework_08.html –Part II

In this blog post i am going to create simple Silverlight Application then using MEF i am going to provide ToolTip for Textbox  UI element.

ToolTips are quite useful for for displaying helpful information when the user hovers over a control. Using MEF we can  Load our ToolTips dynamically and more over useful and nicer looking.

After creating new SL Application first you need Add the following references to the project. you can find these Assembly in Silverlight SDKS folder.

 

Here is my  XAML Code and UI Look and Feel.

<UserControl x:Class="MEFToolTip.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400">

    <Grid x:Name="LayoutRoot" Background="White">
        <Border BorderBrush="Green" BorderThickness="5">
        <StackPanel VerticalAlignment="Top" HorizontalAlignment="Center" Width="350">
            <TextBlock Text="Tool Tip Using MEF" FontSize="30"></TextBlock>
            <StackPanel Margin="10" Width="300">
                        <TextBox Width="250"  Height="50" Name="txtbox" BorderBrush="Brown" BorderThickness="5"></TextBox>
                  </StackPanel>
            </StackPanel>
        </Border>
    </Grid>
</UserControl>

Now i am going to add another Silverlight project (User Control) where i will designed my Tooltip and using MEF i will plug into the above TextBox.

Export

namespace TooTipPlugin
{
    [Export(typeof(UserControl))]     
    public partial class SLToolTip : UserControl
    {
        public SLToolTip()
        {
            InitializeComponent();
        }
    }
}

Import and Compose in Main Application

namespace MEFToolTip
{
    public partial class MainPage : UserControl
    {
        [ImportMany(typeof(UserControl),AllowRecomposition=true)]
        public IEnumerable<UserControl> toolTip { get; set; }
        public MainPage()
        {
            InitializeComponent();
          //  PartInitializer.SatisfyImports(this);
            var catalog = new PackageCatalog();
            catalog.AddPackage(Package.Current);
            Package.DownloadPackageAsync(new Uri("TooTipPlugin.xap", UriKind.Relative), (s, p) => catalog.AddPackage(p));
            var container = new CompositionContainer(catalog);
            container.ComposeParts(this);
            this.Loaded += new RoutedEventHandler(MainPage_Loaded);
        }

        void MainPage_Loaded(object sender, RoutedEventArgs e)
        {
            
            foreach (var item in toolTip)
            {

               ToolTipService.SetToolTip(txtbox, item );
            }
        }
    }
}

Next blog post I will show how to use Metadata so that we can apply a Tooltip from List of available Imports. 

Nandri(Thanks)

SreenivasaRagavan